Bug summary

pyplot.contour raises IndexError when Z is specified as Z=a.

Code for reproduction

import matplotlib.pyplot as plt
plt.contour(Z=np.random.rand(30, 30))

Actual outcome

Expected outcome

Additional information

No response

Operating system

OS/X

Matplotlib Version

3.6.2

Matplotlib Backend

module://matplotlib_inline.backend_inline

Python version

Python 3.8.15

Jupyter version

6.5.2

Installation

pip